Cryogenic air separation plant with reduced liquid drain loss

Abstract

A cryogenic air separation plant and method of operation wherein, after an interruption in operation, liquid from the sump of a lower pressure column and liquid from the sump of a higher pressure column is passed to a condenser, preferably an argon column top condenser, prior to the restarting of the plant.

1. A cryogenic air separation plant comprising a lower pressure column, a higher pressure column, and at least one condenser, each of the lower pressure column and the higher pressure column having a sump located at the bottom thereof, means for passing liquid from the sump located at the bottom of the lower pressure column to said condenser, and means for passing liquid from the sump located at the bottom of the higher pressure column to said condenser. 
     
     
       2. The cryogenic air separation plant of  claim 1  wherein the condenser is a top condenser of an argon column. 
     
     
       3. The cryogenic air separation plant of  claim 2  wherein the means for passing liquid from the sump located at the bottom of the lower pressure column passes liquid to the argon column top condenser, and the means for passing liquid from the bottom of the higher pressure column passes liquid to the argon column top condenser. 
     
     
       4. The cryogenic air separation plant of  claim 1  wherein the means for passing liquid from the sump located at the bottom of the lower pressure column to the condenser comprises a liquid pump. 
     
     
       5. The cryogenic air separation plant of  claim 1  wherein the means for passing liquid from the sump located at the bottom of the higher pressure column to the condenser comprises a liquid pump. 
     
     
       6. A method for restarting a cryogenic air separation plant after an interruption in operation, said cryogenic air separation plant comprising a lower pressure column, a higher pressure column, and a condenser, each of the lower pressure column and the higher pressure column having a sump located at the bottom thereof, said method comprising passing liquid from the sump located at the bottom of the lower pressure column to the condenser, passing liquid from the sump located at the bottom of the higher pressure column to the condenser, and restarting the cryogenic air separation plant. 
     
     
       7. The method of  claim 6  wherein the cryogenic air separation plant further comprises an argon column with a top condenser, and liquid from the sump located at the bottom of the lower pressure column is passed to the argon column top condenser. 
     
     
       8. The method of  claim 6  wherein the cryogenic air separation plant further comprises an argon column with a top condenser, and liquid from the sump located at the bottom of the higher pressure column is passed to the argon column top condenser. 
     
     
       9. The method of  claim 6  further comprising recovering nitrogen product from the lower pressure column. 
     
     
       10. The method of  claim 6  further comprising recovering oxygen product from the lower pressure column.